JP2000191157A - Paper feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To give frictional resistance in rotation to a supply roller using a coil spring, make the supply roller contact with a paper sheet and separate from the sheet using the frictional resistance and prevent application of back tension on the sheet fed by a feed roller. SOLUTION: A supply roller 1 is installed on a support body 6 free to oscillate and installed on a rotating drive shaft in a paper feeding device on which a paper sheet P delivered by the supply roller 1 is fed by the feed roller and the supply roller 1 is separated from the sheet P when feeding the sheet P by the feed roller. Frictional resistance is generated by a coil spring 8 fitted on a rotary shaft 12 of the supply roller 1. A driven side gear 71 of the supply roller 1 is engaged with a driving side gear 72 of the rotating drive shaft 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeder used for feeding paper in a facsimile machine, a copying machine, etc., and more particularly to a paper feeder for feeding paper fed by a supply roller.
The present invention relates to a sheet feeding device that performs an operation of feeding a printing unit or the like by a feed roller.

[0002]

2. Description of the Related Art Conventionally, after a supply roller feeds out a sheet stacked on a tray toward a feed roller, the supply roller separates from the sheet and back tension is applied to the sheet while the sheet is fed by the feed roller. In a sheet feeding apparatus which prevents such a situation, a so-called D-cut roller in which one portion in a circumferential direction is omitted is used as the supply roller.

On the other hand, JP-A-6-72581 and JP-A-4-135530 disclose techniques relating to an automatic sheet feeder. In these automatic paper feeders, a spring clutch is used to operate a shutter for blocking the originals from being pushed into the paper feed rollers when the originals are stacked. Further, the spring clutch converts the rotational force of the paper feed roller rotating shaft into a swinging motion of a frame in which the shutter interlocks via a torsion coil spring.

[0004]

However, in the prior art using a D-cut roller as a supply roller, a design is made such that the leading edge of the sheet reaches the feed roller when the supply roller makes one rotation. In addition, there is a need for complicated control such as stopping the rotation of the supply roller for each rotation or restarting the rotation of the supply roller in synchronization with the timing of feeding the subsequent sheet. However, there was a problem that the cost was high.

On the other hand, the technology disclosed in JP-A-6-72581 or JP-A-4-135530 operates a shutter for blocking a document (paper) from being pushed into a paper feed roller. The present invention does not relate to a technology of a paper feeder intended to feed a sheet fed by a supply roller by a feed roller, which is intended by the present invention.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems and situations. Even when the above-described D-cut roller is not used as a supply roller, when the paper is fed by the feed roller, the paper is fed. It is an object of the present invention to provide a sheet feeding device capable of separating a supply roller used for feeding out to a roller from the sheet so as to prevent the back tension from being applied to the sheet.

Another object of the present invention is to provide an inexpensive sheet feeder to which a sheet fed by a feed roller is not subjected to back tension.

[0008]

According to the present invention, there is provided a paper feeding apparatus in which a sheet fed by a normal rotation of a supply roller is fed by a normal rotation of a feed roller, and the sheet is fed by the feed roller. In the sheet feeding device in which the supply roller is separated from the sheet,

The supply roller is mounted on a support rotatably mounted on a rotary drive shaft so as to be able to rotate forward and reverse, and the supply roller comes into contact with the paper at an operating position and a retracting position separating from the paper. A swing range regulating mechanism that regulates a swing range of the support so as to be displaced between the driven roller and a driven gear fixed to a rotation shaft of the supply roller and a drive fixed to the rotation drive shaft. A side gear is meshed with the supply roller and means for imparting frictional resistance to the supply roller when the supply roller rotates is provided.

In the present invention, the swing range regulating mechanism corresponds to, for example, a tray for stacking sheets and a stopper provided opposite to the tray. In this case, when the swing range of the support is regulated by the tray, the supply roller moves to the operating position and is in contact with the sheets stacked on the tray, and the swing range of the support is regulated by the stopper. The supply roller has moved to the retreat position and is separated from the sheet.

Further, in the present invention, frictional resistance is given to the supply roller during rotation by the above-mentioned means. Therefore, when the drive side gear is rotated forward together with the rotary drive shaft and the rotational force of the drive side gear is transmitted to the driven side gear, the swing range of the support is regulated and the supply roller comes into contact with the paper at the operating position. , The driven gear does not rotate, and only when the supply roller reaches the operating position and abuts on the sheet, the driven gear rotates forward to feed the sheet. In addition, the contact force of the supply roller against the sheet has a magnitude commensurate with the magnitude of the frictional resistance applied to the supply roller by the above means. Also, when the driving gear is rotated in reverse with the rotary drive shaft and the rotational force of the driving gear is transmitted to the driven gear,
The driven gear does not rotate until the supply roller reaches the retracted position at which the supply roller is separated from the paper by restricting the swing range of the support, and only when the supply roller reaches the retracted position and is separated from the paper, the driven side The gears reverse.

As means for imparting frictional resistance to the supply roller, an elastic body interposed between the support and the end face of the supply roller and pressed against them can be used. The elastic body mentioned here includes various forms of rubber, a spring body, an elastic plastic, and the like such as a plate, a tube, and a coil. When a spring body is used as the elastic body, the spring body is a coil spring that is fitted and held on the rotation shaft of the supply roller and is interposed between the support and the end face of the supply roller. It is desirable to adopt a configuration. When the above-mentioned coil spring is used as means for imparting frictional resistance to the supply roller, the coil spring acts as a so-called friction spring, and the swinging operation of the supporting member due to the forward or reverse rotation of the driving gear is stabilized. Further, since it is easy to increase or decrease the force of the coil spring, it is also easy to increase or decrease the contact force of the supply roller against the sheet when the supply roller moves to the operating position.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an exploded perspective view showing a main part of a paper feeder according to the present invention, FIG. 2 is a front view of the main part, and FIGS. It is the schematic side view shown.

In this paper feeder, as shown in FIG. 3, when the supply roller 1 rotates forward (arrow a) in contact with the sheet P, the sheet P is fed out by the supply roller 1, and the leading end P1 of the sheet P is moved. It reaches the feed roller 2 as shown in FIG. Then, as shown in FIG. 4, when the paper P is fed by the forward rotation of the feed roller 2 (arrow b) to the printing unit 4 in which the printing cassette 3 is disposed as shown by the arrow X, the supply roller 1 is moved to the same position. As shown in the figure, the sheet P is separated from the sheet P.

As shown in FIGS. 3 and 4, the sheets P are stacked on a tray 5 having an inclined posture.
The leading end P1 of the paper P when stacked on the tray 5 is supported by a paper receiving surface 51 provided at the lower end of the tray 5. Therefore, when the supply roller 1 contacts the paper P stacked on the tray 5 and rotates forward, the paper P
Is fed out of the tray 5 and the leading end P1 of the sheet
1 and is guided by the paper guide 52 to reach the feed roller 2. The feed roller 2 is provided with a tension roller 21. When the paper P is fed to the printing unit 4 by the feed roller 2, the tension roller 21 presses the paper P against the feed roller 2. Therefore, the paper P is fed by a length corresponding to the rotation amount of the feed roller 2.

As shown in FIG. 1 and FIG.
Is that the rotating shaft 12 is provided on the left and right bearing plate portions 61,
In addition to being rotatably inserted and supported in bearing holes 62, 62 of 61, a driven gear 71 is fixedly attached to one end of the rotating shaft 12, and the other end of the rotating shaft 12 is made of a metal wire. Coil spring 8 fitted and held,
One end of the coil spring 8 is in elastic contact with the end face of the supply roller 1, and the other end is in elastic contact with the left bearing plate 61. The rotary drive shaft 9 is inserted and supported in the other bearing holes 63, 63 of the left and right bearing plate portions 61, 61. A drive gear 72 is fixed to the rotation drive shaft 9 and meshes with the driven gear 71. The coil spring 8 is an example of a unit for applying frictional resistance to the supply roller 1 when the supply roller 1 rotates.

The rotation of the motor (not shown) is transmitted to the rotary drive shaft 9. The rotation of the rotation drive shaft 9 is
Control is performed so as to change from normal rotation to reverse rotation in accordance with the timing at which the feed roller 2 starts rotating, and to change from reverse rotation to normal rotation in accordance with the timing when the paper P stacked on the tray 5 is fed out. Further, the tray 5 is located on one side of the support 6, and a stopper 10 is provided on the opposite side of the tray 5 with the support 6 interposed therebetween.
Is located. Of these, the tray 5 regulates the swing range when the support 6 swings in the direction approaching the tray 5, and the supply roller 1 comes into contact with the sheets P stacked on the tray 5 at the operating position (see FIG. 3). The stopper 10 regulates a swing range when the support 6 swings in a direction away from the tray 5 and moves the supply roller 1 to a retracted position where the supply roller 1 separates from the paper P. Has a role to determine. Therefore, the swing range of the support 6 is regulated by the tray 5 and the stopper 10 such that the supply roller 1 is displaced between an operation position where the supply roller 1 contacts the sheet P and a retracted position where the supply roller 1 separates from the sheet P. A swing range regulating mechanism is formed.

The coil spring 8 shown in FIGS. 1 and 2 has a function of applying a frictional resistance corresponding to the force of the coil spring 8 to the supply roller 1 when the supply roller 1 rotates.

For this reason, as shown in FIG. 3, when the driving gear 72 is rotated forward together with the rotary driving shaft 9 as shown by an arrow R1 and the rotational force of the driving gear 72 is transmitted to the driven gear 71, the supply roller When the sheet 1 is not in contact with the sheet P, the rotational force of the driving gear 72 is used to swing the support 6 as indicated by the arrow M via the driven gear 71 and the rotating shaft 12. Only when the supply roller 1 reaches the operating position where the supply roller 1 comes into contact with the sheet P as shown in FIG. 3 by the swing of the support 6 at this time, the rotational force of the drive gear 72 rotates the driven gear 71 forward. The supply roller 1 is rotated forward (arrow a) at that time.
As a result, the paper P is fed out of the tray 5. In this case, if the spring force of the coil spring 9 is large, the frictional resistance is also large, so that the contact force of the supply roller 1 against the sheet P is increased in proportion to the spring force of the coil spring 9. Conversely, if the spring force of the coil spring 9 is small, the above-mentioned frictional resistance is also small, so that the contact force of the supply roller 1 against the sheet P is reduced in proportion to the spring force of the coil spring 9. From this, it can be said that by adjusting the spring force of the coil spring 9, it is possible to increase or decrease the contact force of the supply roller 1 with respect to the sheet P when feeding the sheet P. In order to adjust the spring force of the coil spring 9, it is effective to change the number of turns, thickness, coil length, and the like of the coil spring 9 to adjust the spring constant.

When the leading edge P1 of the sheet P fed from the tray 5 by the supply roller 1 reaches the feed roller 2 as shown in FIG. 4, the rotation drive shaft 9 starts to rotate in reverse timing. In this way, as shown in FIG. 4, when the driving gear 72 is rotated in the reverse direction as indicated by the arrow R2 together with the rotary driving shaft 9 and the rotational force of the driving gear 72 is transmitted to the driven gear 71, the support 6 moves to the stopper 10. In the non-contact state, the rotational force of the driving gear 72 is used to swing the support 6 through the driven gear 71 and the rotating shaft 12 as shown by the arrow N. Only when the support 6 contacts the stopper 10 and the supply roller 1 reaches the retreat position due to the swing of the support 6 at this time, the rotational force of the driving gear 72 reversely rotates the driven gear 71. Will be used to make it happen. When the feed roller 2 starts rotating and feeds the paper P to the printing unit 4, the support 6 is swung as indicated by an arrow N and the supply roller 1 is separated from the paper P. Roller 2
No back tension is applied to the paper P fed by the printer. This is useful for improving the stability of the feeding state of the paper P by the feed roller 2 and improving the printing quality.

In this embodiment, the coil spring 8 made of a metal wire is used as means for imparting frictional resistance to the supply roller 1 when the supply roller 1 rotates. In addition to the coil spring 8 as described above, a leaf spring made of a metal plate is used,
Alternatively, various forms of rubber, such as a plate, a cylinder, and a coil, or an elastic plastic may be used.

[0022]

According to the present invention, the supply roller is provided with frictional resistance during rotation by using an elastic body such as a coil spring, and the supply roller is brought into contact with the paper by using the frictional resistance or the paper is removed from the paper. Since the paper can be separated from the paper, the paper is fed to the feed roller when the paper is fed by the feed roller without using a conventional D-cut roller as the supply roller. It is possible to provide a paper feeder capable of preventing the supply roller used for feeding out from the paper so as to prevent the back tension from being applied to the paper, and at the same time to provide a paper feeder which is inexpensive and easy to control. It becomes possible to provide a device.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view showing a main part of a sheet feeding device according to the present invention.

FIG. 2 is a front view of the main part.

FIG. 3 is a schematic side view showing the overall structure of the sheet feeding device when feeding out a sheet.

FIG. 4 is a schematic side view showing the overall structure of a sheet feeding device during sheet feeding.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Supply roller 2 Feed roller 5 Tray (oscillation range regulation mechanism) 6 Support body 8 Coil spring (means for giving frictional resistance to supply roller) 9 Rotation drive shaft 10 Stopper (oscillation range regulation mechanism) 12 Rotation axis 71 Drive-side gear 72 Drive-side gear P Paper

Claims (4)

[Claims] 1. A sheet feeding device in which a sheet fed by a forward rotation of a supply roller is fed by a forward rotation of a feed roller, and the supply roller is separated from the sheet when the sheet is fed by the feed roller. In the above, the supply roller is attached to a support that is swingably attached to a rotary drive shaft so that the supply roller can rotate forward and backward, and the supply roller comes into contact with the paper at an operation position and a withdrawal position at which the supply roller separates from the paper. A swing range regulating mechanism that regulates a swing range of the support so as to be displaced between the driven roller and a driven gear fixed to the rotation shaft of the supply roller and a driven gear fixed to the rotation shaft of the supply roller. A gear that meshes with a gear and that includes means for imparting frictional resistance to the supply roller when the supply roller rotates. Location. 2. The apparatus according to claim 1, wherein the means for imparting frictional resistance to the supply roller is an elastic body interposed between the support and an end face of the supply roller and pressed against them. Paper feeder. 3. The sheet feeding device according to claim 2, wherein the elastic body is a spring. 4. The paper feeder according to claim 3, wherein the spring body is a coil spring fitted and held on a rotation shaft of the supply roller and interposed between the support and an end face of the supply roller. apparatus.